Mid-Infrared Silicon-on-Insulator Fourier-Transform Spectrometer Chip

4 pags., 4 figs.Mid-infrared absorption spectroscopy is highly relevant for a wide range of sensing applications. In this letter, we demonstrate a Fourier-transform spectrometer chip based on the principle of spatial heterodyning implemented in the silicon-on-insulator waveguide platform, and operating near 3.75-μm wavelength. The spectrometer comprises a waveguide splitting tree feeding to an array of 42 Mach-Zehnder interferometers with linearly increasing optical path length differences. A spectral retrieval algorithm based on calibration matrices is applied to the stationary output pattern of the array, compensating for any phase and amplitude errors arising from fabrication imperfections. A spectral resolution below 3 nm is experimentally demonstrated.This work was supported by the Engineering and Physical Sciences Research Council through the MIGRATION project under Grant EP/L01162X/1. The work of A. V. Velasco was supported in part by the Spanish Ministry of Economy under Project TEC2012-37958-C02-02 and Project TEC2012-37958-C02-01, in part by the Community of Madrid under Project S2013/MIT-2790, and in part by The European Association of National Metrology Institutes through European Metrology Research Programme Project under Grant JRP IND14 FREQUENCY and PhotInd Project under Grant JRP-i22 IND22. The work of G. Z. Mashanovich was supported by the Royal Society through the University Research Fellowship. M. Nedeljkovic, A. Z. Khokhar, and G. Z. Mashanovich are with the Optoelectronics Research Centre, University of SouthamptonPeer reviewe